The present invention relates generally to identifying locations of lightning strikes.
Electronic equipment is susceptible to damage caused by nearby lightning strikes. The accurate knowledge of a lightning striking point is important to determine which equipment or system needs to be tested following a lightning strike. Existing lightning location systems can provide coverage of a wide area. For example, a lightning location system can provide coverage of an area having a 30 km radius. This system, however, has a 50% confidence region of about 500 meters. That is, the system has a 50% confidence that a lighting strike is within 500 meters of an identified location. As such, present lightning location systems cannot be used to determine whether a lightning strike occurred inside or outside of a parameter of an area of concern. One such application of a lightning location system is a Space Shuttle launch pad for the National Aeronautics and Space Administration (NASA). By accurately determining lightning strike locations, electronic equipment located within the launch pad area can be tested and/or reset to avoid erroneous operation.
One method of determining the location of lightning strikes uses a set of video cameras that are pointed in different directions within the area of concern. If a lightning strike occurs within the field of view of three or more cameras, the location of the strike can be determined. However, if the cameras are not pointed in the correct direction, or either an object or a heavy rain downpour obscures their field of view, it is difficult or impossible to accurately determine a striking point of the lightning. Further, this method has a relatively large uncertainty and does not facilitate an accurate location of the exact point of contact to the ground.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for the system and method to accurately approximate locations of lightning strikes.
The above-mentioned problems with lightning strike location and other problems are addressed by the present invention and will be understood by reading and studying the following specification.
In one embodiment, a system to determine an approximate location of lighting strikes comprises an electric field sensor, a plurality of acoustic sensors collocated with the electric field sensor, and a processor to determine the location of lighting strikes based on a time differential between an electric field pulse and a acoustic wave.
In another embodiment, a system to determine an approximate location of lighting strikes comprises an electric field sensor, a plurality of acoustic sound sensors collocated with the electric field sensor, a temperature sensor, and a processor. The processor determines the location of lighting strikes based on a time differential between an electric field pulse and a acoustic wave. The processor uses a look-up table to compensate for ambient temperature measured by the temperature sensor.
A method for determining an approximate location of a lightning strike comprises collecting lightning strike information, including a time of arrival of an electric field pulse using an electric field sensor and time of arrival data of an associated sonic wave from a lightning strike. The sonic wave data is detected using a plurality of acoustic sensors collocated with the electric field sensor, and processing the lightning strike information to approximate the location of the lightning strike.
Another method for determining an approximate location of a lightning strike comprises detecting an electric field signal, detecting a sonic pulse with a plurality of collocated sensors, measuring a time of arrival difference between the electric field signal and the sonic pulse, and determining a range, azimuth and elevation of the lighting strike.